Even feeding attachment for sewing machines

ABSTRACT

An attachment for a sewing machine in which a work feeding foot movable with the work and a stationary presser foot are alternately pressed against the work during sewing. A leaf spring carried in the attachment is attached to the work feeding foot and between successive stitches returns the work feeding foot to a central position from which the work feeding foot may be shifted either forwardly or rearwardly to cooperate with a forward or reverse direction of work feed. The leaf spring as well as the operating mechanism of the attachment is sustained in a molded support block having integral rivet studs which can be deformed after assembly to secure the attachment parts together.

United States atent 1 [111 3,73Mt7 Ritter et a1. May 1, 1973 EVEN FEEDING ATTACHMENT FOR SEWING MACHINES Primary Examiner-Werner H. Schroeder Att0rney-Marshall .1. Breen et a1.

[ 5 7] ABSTRACT An attachment for a sewing machine in which a work feeding foot movable with the work and a stationary presser foot are alternately pressed against the work during sewing. A leaf spring carried in the attachment is attached to the work feeding foot and between successive stitches returns the work feeding foot to a central position from which the work feeding foot may be shifted either forwardly or rearwardly to cooperate with a forward or reverse direction of work feed. The leaf spring as well as the operating mechanism of the attachment is sustained in a molded support block having integral rivet studs which can be deformed after assembly to secure the attachment parts together.

4 Claims, 8 Drawing Figures Patented May 1 1973 3,730,117

2 Sheets-Sheet 1 Fig.| I20 66 Patented May 1, 1973 2 Shee cs-Shea t 2 EVEN FEEDING ATTACHMENT FOR SEWING MACHINES BACKGROUND OF THE INVENTION Prior even feeding attachments for sewing machines which were capable of cooperating with forward or reverse directions of feed of the sewing machine to which they might be applied, have required sliding support for the work feeding foot of the attachment in addition to means such as the opposed coil springs disclosed in the construction of the U.S. patent application Ser. No. 133,925 filed Apr. 14, l97l of W. J. Edwards for returning the work feeding foot to an intermediate position. As a result, the frictional resistance to movement of the work feeding foot of these prior even feeding attachments was relatively high; sufficiently so as to constitute a deterrent to ready return of the work feeding foot to a neutral position between feed strokes. The problem could not be solved by increasing the spring force acting to return the work feeding foot because such spring force has to be overcome during the feeding stroke and if it is raised to an overly high value, becomes an impediment to the feed assist which is the principal purpose of the device.

BRIEF SUMMARY OF THE INVENTION It is an object of this invention to provide an even feeding attachment for a sewing machine cooperable with either forward or reverse directions of sewing machine feed in which the work feeding foot is subjected to minimal frictional resistance to movement in the direction of feed, with the result that the return spring force may be reduced to minimize its detrimental effect upon the work feed assist provided by the attachment. This object of the invention is attained by the use of a leaf spring anchored in the body of the attachment to which the work feeding foot is pivotally attached to provide the only support for the work feeding foot.

It is also an object of this invention to provide a simple and economical attachment construction whereby the leaf spring support for the work feeding foot may be included readily and whereby the assembly of the attachment may be completed quickly and inexpensively.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings ofa preferred form of this invention:

FIG. 1 represents an end elevational view of a fragment ofa sewing machine partly broken away and illustrated in cross section, showing an even feeding attachment ofthis invention applied thereto,

FIG. 2 is a right side elevational view of the attachment of FIG. 1 including only the needle and presser bars of the sewing machine and with the attachment side plate shown in phantom lines.

FIG. 3 is a left side elevational view of the attachment of FIG. 1 with the side plate and presser foot removed,

FIG. 4 is a left side elevational view of the complete attachment shown with the sewing machine presser bar and with the needle bar at the bottom of the stroke,

FIG. 5 is a left side elevational view of the complete attachment showing the sewing machine needle bar in elevated position and the sewing machine work feed mechanism operating in the forward direction of feed,

FIG. 6 is a view similar to FIG. 5 but illustrating the sewing machine work feeding mechanism operating in a reverse direction of feed,

FIG. 7 is an enlarged perspective view of a portion of the attachment supporting block showing the leaf spring anchoring cavity therein, and

FIG. 8 is a top plan view of the attachment of this invention.

Referring to FIG. 1, 11 indicates generally the frame of a sewing machine of which 12 is a work supporting bed from which rises a standard 13 supporting a bracket arm 14 overhanging the bed. Journaled for endwise reciprocation in the bracket arm is a needle bar 15 to which a needle clamp 16 is secured for fastening a needle 17 thereon. Also endwise slidable in the bracket arm 14 is a presser bar 18 formed with a slabbed seat 19 of the conventional type adapted to accommodate a presser foot. The presser bar is preferably spring biased downwardly as is conventional in sewing machine construction.

Also forming a part of the conventional sewing machine to which the present invention may be applied is a work feeding mechanism including a feed advance pitman 30 which may be located in the sewing machine standard 13 and pivoted at 31 to a rock arm 32 on a feed advance rock shaft 33 in the sewing machine bed. A rock arm 34 fast on the feed advance rock shaft 33 is pivotally connected at 35 to a feed bar 36 carrying a feed dog 37 which works upwardly through slots 38 in a throat plate 39 on the work supporting bed to engage and transport work fabrics W transversely across the sewing machine bed. The feed bar 36 is pivoted at 40 to a link 41 which is pivotally connected at 42 to a rock arm 43 projecting from a feed lift rock shaft 44 in the sewing machine bed. For regulating the magnitude and direction of work feed motion, a slotted guide block 50 is pivoted as at 51 in the sewing machine standard 13 and embraces a slide block 52 which is pivoted at 53 to the feed advance pitman 30. An operator influenced handle 54 projecting from the slotted guide block 50 may be used to select the angular position of the guide block which regulates the stitch length and direction in a manner well known in the sewing machine art.

The attachment of the present invention provides a device which may replace the conventional presser foot on the presser bar 18 of the sewing machine and which is organized so as to assist the conventional sewing machine feed dog 37 to feed a plurality of plies of work fabric W evenly and equally regardless of the magnitude or direction of the work feed stroke of the feed dog 37. Theattachment of this invention comprises a support block 60 which is preferably molded as one integral element. The support block 60 includes a body portion 61 formed with a central vertical rib 62 from which a peripheral flange 63 extends evenly on opposite sides to define shallow recesses 64 and 65 one at each side of the support block 60. A shank 66 projecting from the body portion 61 of the support block is formed complemental to the slabbed seat 19 on the presser bar and includes a notch 67 to accommodate a fastening screw 68 by which the attachment may be secured to the presser bar 18 of the sewing machine.

Bosses 70 are formed so as to extend from the central vertical rib of the support block body portion in each of the shallow recesses 64 and 65 at each side of the support block. Each boss 70 is formed with an integral rivet 71 projecting therefrom adapted to pass through apertures 72 formed in a pair of side plates 73, 74 located one at each side of the support block. Heads may be formed on each of the rivets 71 by heating and upsetting the rivets after the side plates 73, 74 are assembled thereon in order to lock the side plates permanently in position on the support block. Each of the side plates is preferably formed with a forwardly extending arm 75, 76, respectively, and between the arms a presser foot 77 is pivotally supported.

The presser foot 77 is, therefore, supported directly on the sewing machine presser bar 18 by the integral support block 60 and side plates 73, 74 which are fastened permanently thereon. The presser foot is formed with a conventional needle accommodating aperture 80 and also with longitudinal slots 81 accommodating a feeding foot 82 which can oppose the sewing machine feed dog 37 and assist the feed dog in feeding multiple plies of work fabric evenly.

The feeding foot 82 is secured at the forward extremity of an elongated preferably rigid bar 83. The bar 83 at the extremity opposite the feeding foot is formed with upturned tabs 84 sustaining a pivot pin 85 by which the bar is pivotally supported on the depending extremity of a leaf spring 86 mounted in the support block 60 of the attachment. The upper extremity of the leaf spring 86 is bifurcated and the branching arms 87, 88 thereof are bent in opposite directions each substantially perpendicular to the leaf spring. The body portion 61 of the support block 60 is formed with a pair of spring orienting posts 89 and 90 which are spaced rela tively to the other and relatively to the peripheral flange 63 so as to define a reception seat for the leaf spring 86 and the bifurcated arms 87, 88 thereof which locks the spring 86 in a predetermined position relatively to the support block. The pivot pin 85 provides the only support for the feeding foot 82 and the bar 83 by which the feeding foot is carried. A light coil spring 91 is preferably arranged in tension between a tab 92 on the bar 83 and a pin 93 formed concentrically within the post 90 in the body portion of the support block 60 providing an upward bias for the feeding foot 82.

As best illustrated in FIG. 2, an operating lever 100 is pivotally sustained on a fulcrum pin 101 in the shallow recess 65 of the support block. The operating lever 100 which is bifurcated as at 102 at its free extremity to embrace a shouldered portion 103 of the clamp screw 104 of the needle clamp 16 on the sewing machine needle bar, projects through a clearance slot 105 in the peripheral flange 63 of the attachment support block. The operating lever 100 carries a pivot pin 106 on which a drive roller 107 is journaled within the hallow recess 65. A bell crank lever 110 pivoted on a fulcrum pin 111 in the support block 60 is formed with one arm 112 extending into cooperative following relationship with the roller 107 on the operating lever 100. The bell crank 110 is formed with another arm 113 carrying an enlarged head 114 adapted to bear against the bar 83 above the feeding foot 82.

The fulcrum pin 111 may provide a rivet like the rivets 71 for securing the side plate 74 to the support block 60. Preferably, the fulcrum pin accommodates a washer 115 between the bell crank lever 110 and the side plate 74 to insure that the bell crank lever will be supported free of binding.

In the operation of the sewing machine with the attachment of this invention applied thereto, the operating lever 100 of the attachment during each upstroke of the sewing machine needle bar 15 will cause the drive roller 107 to shift the bell crank lever 110 as shown in FIG. 2 causing the block 114 on the bell crank lever 110 to urge the feeding foot 82 downwardly. When the feeding foot 82 engages the work fabric in opposition to the sewing machine feed dog 37, the block 114 will become the fulcrum for continued movement of the bell crank 110 and by way of the pin 111 the support block will be elevated and will carry upwardly with it the presser foot 77. During each upstroke of the needle, which corresponds to the active feed stroke of the sewing machine feed dog 37, therefore, the attachment presser foot 77 will be removed from the work and the feeding foot 82 will be engaged therewith. The leaf spring 86 depends freely from the support block 60 through a gap 120 in the peripheral flange 63 thereof and is free to flex in either direction from a relaxed central position so that the feeding foot 82 is free to move with the work in either direction forward or reverse in which the sewing machine feed dog is adjusted to advance the work fabrics. In FIG. 5 the position of parts at the conclusion of the feeding stroke in the forward direction is illustrated and the leaf spring 86 is shown flexed toward the rear of the attachment. In FIG. 6 the position of parts is shown at the conclusion of a feed stroke in the reverse direction with the leaf spring illustrated flexed toward the front of the attachment. Regardless of which direction the sewing machine feed partakes, when the needle bar 15 of the sewing machine next is reciprocated toward the work, the operating lever 100 will move downwardly carrying the drive roller 107 out of engagement with the bell crank 100 and the block 114 will be elevated allowing the feeding foot 82 to shift upwardly in response to the light return spring 91. The lever 110 will be rocked and will allow the presser foot 77 of the attachment to be lowered into engagement with the work fabrics so that the feeding foot 82 will rise out of engagement with the top ply of work fabrics W and the leaf spring 86 will be free to return to its relaxed position carrying the feeding foot into a central position again in readiness for movement either in forward or reverse direction on the succeeding work feeding stroke of the sewing machine feed dog 37.

Since the feeding foot 82 is supported solely by a pivotal connection with the leaf spring 86, resistance to sliding movement of the feeding foot and binding forces tending to resist movement of the feeding foot are minimized.

Assembly of the attachment is also greatly facilitated by the construction of this invention. In the shallow recess at one side of the support block the levers and are assembled on the fulcrum pins 101 and 111 respectively. The washer is placed on the pin 111 and the side plate 74 is placed in position. In the shallow recess 64 at the other side of the support block, the springs 86 and 91 are simply positioned on the posts 89, 90 and the pin 93 and the side plate 73 is placed in position. When heads are formed on the rivets 71, the assembly of the attachment is completed.

Having set forth the nature of this invention, what is claimed herein is:

1. An attachment adapted for use with a sewing machine having a presser bar and a needle bar, said attachment comprising a support block attachable to said sewing machine presser bar, a presser foot attached to said support block, an operating lever system drivingly engageable with said needle bar and carried on said support block, and a work feeding foot shiftable in a path lengthwise along said presser foot and engageable by said operating lever system for depression thereby beneath the level of said presser foot, characterized in that a leaf spring is connected at one extremity to said work feeding foot and said leaf spring is anchored at the other extremity in said support block in such a position that when the leaf spring is relaxed the work feeding foot will be located thereby substantially midway in said path along said presser foot, and so that movement of said work feeding foot in either direction along said path will be resisted by forces generated in said leaf spring.

2. An attachment as set forth in claim 1 in which said leaf spring includes a substantially straight body portion which is bifurcated at the extremity opposite said pivotal connection with said work feeding foot, said leaf spring bifurcations each being bent outwardly in opposite directions substantially at right angles to said body portion, said support block being formed with a reception seat snugly accommodating said leaf spring bifurcations so as to anchor said leaf spring body portion in a central position substantially perpendicular to the path of work feeding foot movement lengthwise along said presser foot toward which said leaf spring will return when flexed by work feeding foot movement in either direction.

3. An attachment as set forth in claim 2 in which side plates are secured to said support block and serve to constrain said leaf spring bifurcations and said reception seat in said support block, and in which said presser foot is pivotally supported between arms projecting from said side plates.

4. An attachment as set forth in claim 3 in which said support block is molded of thermoplastic material including integral rivet studs protruding from each side thereof, said side plates each being formed with rivet accommodating apertures, said rivet studs being initially formed of sufficient length as to protrude through said rivet accommodating apertures to provide sufficient material for rivet heads when said rivet studs are heated and upset after assembly of said side plates thereon. 

1. An attachment adapted for use with a sewing machine having a presser bar and a needle bar, said attachment comprising a support block attachable to said sewing machine presser bar, a presser foot attached to said support block, an operating lever system drivingly engageable with said needle bar and carried on said support block, and a work feeding foot shiftable in a path lengthwise along said presser foot and engageable by said operating lever system for depression thereby beneath the level of said presser foot, characterized in that a leaf spring is connected at one extremity to said work feeding foot and said leaf spring is anchored at the other extremity in said support block in such a position that when the leaf spring is relaxed the work feeding foot will be located thereby substantially midway in said path along said presser foot, and so that movement of said work feeding foot in either direction along said path will be resisted by forces generated in said leaf spring.
 2. An attachment as set forth in claim 1 in which said leaf spring includes a substantially straight body portion which is bifurcated at the extremity opposite said pivotal connection with said work feeding foot, said leaf spring bifurcations each being bent outwardly in opposite directions substantially at right angles to said body portion, said support block being formed with a reception seat snugly accommodating said leaf spring bifurcations so as to anchor said leaf spring body portion in a cenTral position substantially perpendicular to the path of work feeding foot movement lengthwise along said presser foot toward which said leaf spring will return when flexed by work feeding foot movement in either direction.
 3. An attachment as set forth in claim 2 in which side plates are secured to said support block and serve to constrain said leaf spring bifurcations and said reception seat in said support block, and in which said presser foot is pivotally supported between arms projecting from said side plates.
 4. An attachment as set forth in claim 3 in which said support block is molded of thermoplastic material including integral rivet studs protruding from each side thereof, said side plates each being formed with rivet accommodating apertures, said rivet studs being initially formed of sufficient length as to protrude through said rivet accommodating apertures to provide sufficient material for rivet heads when said rivet studs are heated and upset after assembly of said side plates thereon. 